AESA Comlinks: DID Reader Has Done Prior Research

In yesterday’s issue, DID covered a request from Australia’s military for information re: combat ID and forward air controller equipment, in preparation for a procurement initiative in that area. Seems only fair that the sharing should go both ways. In “Elec Tricks: Turning AESA Radars Into Broadband Comlinks,” DID chronicled some very intriguing work by Northrop Grumman and L-3 that turns advanced AESA devices into secure broadband data and communications links, as well as extremely effective radars. Dr. Carlo Kopp of Air Power Australia recently wrote to DID with this interesting addendum:

“My PhD thesis project completed in 1999 involved the theoretical modelling required for the adaptation of AESAs as high speed long range datalinks and their adaptation to networking. It was a monster project involving around 1000 large scale simulation runs on a 60 CPU cluster (eq to a Cray) and ended up with a 480 page thesis… In practical terms Northrop-Grumman and L-3 have yet to hit the really hard problems…”

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Dr. Kopp, an academic and industry consultant based in Melbourne, Australia is currently involved in a major research effort to develop a highly secure wireless ad hoc networking protocol, as well as basic research in the information theory foundations of Information Warfare. He says he’d be happy to talk to Northrop Grumman and/or L-3 if they wish.

As he put it to DID:

“In 1997 it occurred to me that power-aperture performance was going to set hard bounds on high speed airborne datalink and network performance, and that AESAs planned for the F-22, F-15, F-16, F/A-18 and JSF would be ideal candidates for solving this problem. I had already at that time started my PhD project at Monash University with a focus on airborne networking, under the supervision of the now late Prof Chris Wallace, inventor of the Peltier cascade, the Wallace tree multiplier and key information theory ideas.

I spent the next 3 years and 4 months in a very intensive effort to model propagation performance and achievable data throughput in AESA based networks, using fighter radars as the baseline for available power-aperture performance. I just about saturated the Monash Uni Linux cluster with computational simulations over a 12 month period, to the extent that the other users revolted.

There is absolutely no doubt that Northrop-Grumman and L-3 are on the right track with this effort and it is gratifying to see them achieve some practical demonstration results.

The reality of this technology is that it has much more potential, especially in terms of achievable range and link bandwidth, but the latter will require some philosophical changes in how Transmit-Receive modules are designed – an issue many radar engineers I canvassed this with over recent years balked at. If we want to maximise the effect of this technology, we need to rethink how we build AESAs.

‘There will be other interesting problems which the Northrop-Grumman/L-3 team will confront, especially in terms of protocols for managing the antenna and encapsulating data. Propagation through the atmosphere at shallow slant angles opens up a whole variety of interesting engineering issues which will need to be solved.

Overall, I see this technology reaching its full potential once current AESAs go through their midlife upgrade cycle during the coming decade, as this will present opportunities to add suitable design optimisations into TR modules and other areas of the system design.

I did offer a proposal for such an AESA datalink adaptation to the Australian Department of Defence in Canberra, in 2002, as part of an unsolicited commercially bid AESA upgrade proposal for the F-111 fleet.”